CHAPTER VI. 

 THE MANURING OF THE CANE/-* 



The cane, in common with other economic plants, has received extensive 

 manurial trials ; from the many published statements available certain of the 

 results are abstracted below, arranged under the districts in which they were 

 made. 



British Guiana. Scard 1 , as the result of an extended series of experi- 

 ments on the Colonial Company's Estates in British Guiana, concluded : 



1. That lime used by itself gave a small pecuniary gain. 



2. That lime associated with manures gives an increase sufficient to pay 

 for itself only when used with larger (2 cwt.) quantities of soluble nitrogen, 

 such as sulphate of ammonia. 



3. That of nitrogenous manures, sulphate of ammonia at the rate of 

 2 cwt. per acre gives the best results. 



4. That ground mineral phosphate appears to give an increased yield 

 compared with superphosphate. 



5. That guanos, especially in conjunction with lime, fall far short of 

 ammonia in beneficial effect. 



6. That an increase of phosphoric acid over the minimum employed 

 (168 Ibs. per acre) fails to give satisfactory pecuniary results. 



7. That neither lime nor manures produce any perceptible difference in 

 the purity of the juice but only affect the weight of cane. 



Harrison 2 concluded as a resume of work on cane manuring : 



1 . That the weight of cane is governed by the amount of readily available 

 nitrogen either naturally present or added as manure. 



2. When applied in quantities containing not more than 40 to 50 Ibs 

 nitrogen per acre, sulphate of ammonia and nitrate of soda are equally 

 effective manures on the majority of soils, but that when the unit of nitrogen 

 is of equal money value it is more economical to supply the former. Dried 

 blood and similar organic manures in which the nitrogen only slowly becomes 

 available are distinctly inferior sources. 



3. Under ordinary conditions of soil and climate and the usual range of 

 prices for sugar, it is not advisable to supply more than 2 cwt. of sulphate of 

 ammonia or 2| cwt. of nitrate of soda per acre. 



4. If circumstances arise in which it is desirable to obtain the maximum 

 yield per acre by the application of more than 50 Ibs. nitrogen per acre, 

 sulphate of ammonia should always be used. 



* I write Manuring in preference to Fertilization, the term used in the United States, for by the 

 latter is properly understood the process of impregnating the female organs of the cane flower. 



55 



